An idea of using cold atomic gases as quantum simulators of systems otherwise inaccessible is already well established and sounds in accordance with an old proposition given by Feynman [1]}, [2]}. For example, this idea has been applied to study a quantum phase transition from a superfluid to a Mott insulator by using a gas of ultracold rubidium atoms in an optical lattice [3]} and to investigate critical phenomena near continuous phase transitions [4]}. A two-dimensional caesium atoms' superfluid was quenched to higher interparticle interactions to observe the Sakharov oscillations, which were predicted to occur at the inflation era of early Universe and are responsible for detected fluctuating cosmic microwave background [5]}. Recently, the Hawking temperature of an analogue black hole was measured experimentally in agreement with the Hawking's theory [6]}. An analogue fluid black hole was created in the Bose-Einstein condensate of rubidium atoms.
